I've been advising everyone new to the series to play the demo of The Witcher - even just to the end of the prologue, as that serves as the best introduction to the lore of TW2 that's easily available (and then forget the gameplay mechanics).

I also enjoy diving into lore, but the lore has to be available in a non-spoilery, official, way. In my review I wished they had included a lore book with the game instead of a cheat/walkthrough book - doing so would most likely satisfy the likes of this reviewer.

Even completing The Witcher is not enough to get full enjoyment/understanding out of the sequel. I required knowledge from the books to appreciate some major elements of the story, and even then I only had a faint grasp on it due to the lack of English translations.